He is to undergo an operation on Friday (June 7) under general anaesthetic, according to BBC News.

The Duke, who turns 92 on June 10, is expected to stay in the hospital for up to two weeks, a Palace spokesperson stated.

He is said to be "in very good health" and it was stressed that it was not an emergency admission.

The Palace has also confirmed that the illness is not connected to a previous ailment the Duke was suffering from earlier this week, when he pulled out of an official engagement for the Royal National Institute of Blind People.

The Prince had previously canceled all his official engagements for May and June. However, he did attend a service at Westminster Abbey on Tuesday to mark Queen Elizabeth's 60th anniversary of her Coronation.

He also made an appearance at a garden party at Buckingham Palace today, where guests stated that he showed no signs of illness.

The Queen will continue her engagements as normal, including a visit to the new BBC studios in Central London tomorrow.